Present-day telecommunications networks typically include one or more Local Exchanges Carriers (LECs) that provide local telephone service, i.e. dial tone, to subscribers. Each LEC has at least one local office switching system at which calls originate and terminate. The LECs lying within a given Local Access Transport Area (LATA) are interconnected so that a call originating at one LEC can terminate at another LEC in the same LATA. Calls originating at a LEC within one LATA destined for a LEC within another LATA, are typically carried by an Inter-eXchange Carrier (IXC), such as by AT&T. Additionally, an IXC typically processes featured calls (i.e., those requiring certain types of processing, such as 500, 700, 800, 888 calls; Operator calls; and local calls associated with Loop resale, for example). A typical IXC network, such as IXC network maintained by AT&T, includes a plurality of interconnected toll switching systems, and one or more data bases in the form of Service Control Points (SCPs), known as Network Control Points (NCPs) within the AT&T network, each containing information regarding call processing.
Presently, all inter-LATA and international toll calls and all featured calls (both local and Inter-LATA) pass from an originating LEC to an originating toll switching system (OS) within the IXC network for processing and routing to their intended destination. For example, Inter-LATA toll calls pass from the OS within the IXC network to a terminating toll switching system (TS) within the IXC network, either directly, or through one of more via toll switching systems (VSs). From the TS, Inter-LATA toll calls pass to a terminating LEC. Featured calls pass from the originating LEC to the OS within the IXC serving that LEC. If the OS does not possess the requisite call processing capability, (i.e., the OS lacks access to an NCP), then the call passes from the OS to a toll switching system having the requisite processing capability. After processing, the call is routed to its intended destination.
The toll switching system that performs the processing for featured calls will hereinafter be referred to as the "hand-off switching system (HS)." As previously discussed, the OS may serve as the HS, depending on the processing capabilities of the OS. Should the OS not possess the requisite processing capability, then the switching system to which the OS hands off the call becomes the HS, and is said to be "associated with" the OS.
Since all inter-LATA toll and international calls and all featured calls presently pass to the HS within the IXC network, increases in toll and featured call traffic result in an increased load on each HS. To accommodate more traffic, additional toll switching systems must be provided, thereby increasing network costs for the IXC.
Thus, there is a need for a technique for local/toll dynamic routing network integration to integrate class-of-service processing with the local and toll networks to provide efficient dynamic route selection to the destination while making efficient use of service processing capabilities as well as network switching and transport capacity, thereby reducing the burden on IXC toll switching systems without significantly increasing the development cost of local switching systems.